1. Field of the Invention
The present invention relates to an ink for ink-jet recording.
2. Description of the Related Art
In an ink-jet recording method, droplets of ink are formed, and all or a part of the formed ink droplets are made to adhere to recording material such as paper to thereby perform recording. In this case, the ink droplets are formed by means of an ink ejection method such as an electrostatic attraction method, a method in which mechanical vibrations or displacements are applied to ink using a piezoelectric element or the like, or a method utilizing pressure generated when a gas bubble is formed by heating ink.
As the ink-jet recording method has come into widespread use, various studies have been conducted for improving the ink. The ink employed in the ink-jet recording method is required to have various characteristics such as no blurring on recording material, capability of forming a uniform high density image, and fast drying on recording material.
It has been proposed to improve the penetrability of ink into recording material by adding a polyalcohol, a polyalcohol derivative and/or a surfactant to an ink for ink-jet recording (Japanese Patent Application Laid-Open Nos. S55-29546, S55-65269 and S62-11781). In these inks, the penetrability into recording material is significantly enhanced to improve the drying properties of an image. In this case, although the drying properties are improved, a problem arises that the extent of blurring increases in the image.
Further, it has been proposed to improve the quality, drying properties, rub fastness and the like of printed material by adding a specific organic solvent to an ink for ink-jet recording (Japanese Patent Application Laid-Open No. 2002-363468). However, this ink requires a drying time of 40 to 50 seconds after printing on paper for preventing a finger and/or paper from being smudged with the ink when a printed portion is rubbed with the finger. Thus, the ink is not considered to have sufficient drying properties.
Moreover, the technology of the abovementioned conventional ink for ink-jet recording has been developed to be applied to a so-called serial method in which printing is performed by moving an ink-jet recording head on recording material in a main scanning direction. On the other hand, a so-called line head method (Japanese Patent Application Laid-Open No. 2003-311955) employs an ink-jet recording head having a length comparable to or longer than the width of the main scanning direction of a recording material. In this case, printing is performed by allowing a recording material to pass under the ink-jet recording head only once without moving the head. The line head method has a printing speed faster than that of the serial method. Therefore, the abovementioned conventional ink for ink-jet recording has a problem that the drying properties are insufficient as an ink employed in the line head method.